Thermal treatment apparatus, method for manufacturing semiconductor device, and method for manufacturing substrate

ABSTRACT

A thermal treatment apparatus, a method for manufacturing a semiconductor device, and a method for manufacturing a substrate, wherein the occurrence of slip dislocation in a substrate during heat treatment is reduced, and a high-quality semiconductor device can be manufactured, are intended to be provided. 
     A substrate support  30  is formed from a main body portion  56  and a supporting portion  58 . In the main body portion  56 , a plurality of placing portions  66  extend parallel, and supporting portions  58  are provided on the placing portions  66 . A substrate  68  is placed on the supporting portion  58 . The supporting portion  58  has a smaller area than an area of a flat face of the substrate, and is formed from a silicon plate having a thickness larger than thickness of the substrate, so that deformation during heat treatment is reduced. The supporting portion  58  is made of silicon, and a layer coated with silicon carbide (SiC) is formed on a substrate-placing face of the supporting portion  58.

This is a Continuation of application Ser. No. 10/528,069 filed Jul. 10,2006, which in turn is a National Stage of PCT/JP03/012353 filed Sep.26, 2003, which claims the benefit of Japanese Patent Application Nos.2003-051244 filed Feb. 23, 2003 and 2002-282231 filed Sep. 27, 2002. Theentire disclosure of the prior applications is hereby incorporated byreference herein in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to thermal treatment apparatus forheat-treating a semiconductor wafer, glass substrate and the like, amethod for manufacturing a semiconductor device, and a method formanufacturing a semiconductor wafer or a glass substrate.

2. Background Art

When a plural number of substrates such as silicon wafers areheat-treated using, for example, a vertical heat treatment furnace, asubstrate support (boat) made of silicon carbide is used. In thesubstrate support, for example, a supporting groove for supporting asubstrate at three points is provided.

In this case, there has been a problem that when the heat treatment isperformed at a temperature of about 1000° C. or more, slip dislocationoccurs in the substrate near the supporting groove, which may grow intoa slip line. When the slip line occurs, flatness of the substratebecomes worse. Therefore, there has been a problem that misalignment ofmask (misalignment of mask due to defocusing or deformation) occurs in alithography process that is one of important processes in a LSImanufacturing process, and thus manufacture of LSI having a desiredpattern is difficult.

As means for solving such a problem, a technique is known, whereinfirst, a dummy wafer is placed in the supporting groove, and then asubstrate to be treated is placed on the dummy wafer (refer to patentliterature 1). The technique intends that the conventionalthree-point-support is changed to face-support using the dummy wafer,thereby stress concentration by empty-weight of the substrate to beprocessed is suppressed and thus warp of the substrate is prevented, andthereby occurrence of the slip dislocation is prevented.

As one of the substrate supports of this type, a boat material such asSi—SiC, on which CVD-SiC coating is formed to prevent impuritycontamination from the material, is known (refer to patent literature2). According to the known example, the CVD-SiC coating is 30 μm to 100μm in thickness. That is, when the thickness of the coating is less than30 μm, impurities are diffused from the boat material to a surface ofthe coating, therefore the object of the CVD coating, or prevention ofimpurity diffusion by the coating, can not be achieved, and when thethickness of the coating is more than 100 μm, a padding condition thatCVD is concentratively deposited onto an edge portion of the boatmaterial occurs, and if the boat (substrate support) is used in thiscondition, burrs are formed, causing particle contamination.

As another conventional example, a substrate support is known, wherein aSiC film is formed onto a base material such as Si-impregnatedsintered-SiC material or graphite by CVD method, so that heatresistance, impact resistance, oxidation resistance, and corrosionresistance are improved (refer to patent literature 3). According to theknown example, thickness of the SiC film is preferably 20 μm to 200 μm,and when it is less than 20 μm, since the SiC film itself is damaged,life of the film may be reduced, and when it is more than 200 μm, theSiC film is easily separated.

As still another conventional example, a jig (boat and the like) made ofSiC is known, wherein the CVD-SiC coating is applied on a surface of thejig, and a SiO₂ film is formed on a surface of the coating (refer topatent literature 4). It is shown from the known example that the SiCcoating is for securing uniformity of a surface of the base material,and the thickness of the SiC film is 100 μm, as a practical example.Moreover, it is shown that the SiO₂ film is formed for preventingreduction in thickness of the base material in dry cleaning using ClF₃,and thickness of the film is desirably 10 Å to 100 μm.

As still another conventional example, it is known that the CVD-SiC iscoated about 100 μm on a surface of a support made of Si—SiC (refer topatent literature 5).

[Patent literature 1] JP-A-2000-223495.

[Patent literature 2] JP-A-2000-164522.

[Patent literature 3] JP-A-2002-274983.

[Patent literature 4] JP-A-10-242254.

[Patent literature 5] JP-A-10-321543.

SUMMARY

However, according to results of experiments by the inventor, althoughthe above conventional examples where the substrate is placed on thedummy wafer become better compared with the example using thethree-point-support, they are insufficient in a point of preventing theslip dislocation because of occurrence of the slip line.

It is considered that this is because since the dummy wafer is thin likethe substrate, for example 700 μm thick, the dummy wafer is deformed dueto difference in thermal expansion generated between the dummy wafer anda substrate support comprising silicon carbide or other stress, and theslip dislocation occurs in the substrate due to the deformation of thedummy wafer.

It is found from the results of the experiments by the inventors of theapplication that in some material or thickness of the film coated on asubstrate-placing face of the supporting portion of the substratesupport, the slip may occur due to a thermal expansion coefficient ofthe film and the like.

Thus, the invention intends to provide thermal treatment apparatus, amethod for manufacturing a semiconductor device, and a method formanufacturing a substrate, wherein the slip dislocation occurring in thesubstrate during heat treatment is reduced, and thus a high-qualitysemiconductor device can be manufactured.

To solve the above problem, a first feature of the invention is thermaltreatment apparatus that performs heat treatment with a substrate beingsupported by a substrate support, wherein the substrate support has amain body portion and a supporting portion which is provided on the mainbody portion and in contact with the substrate, and the supportingportion comprises a silicon platelike-member having a larger thicknessthan thickness of the substrate. The thickness of the supporting portionis larger than the thickness of the substrate, preferably 10 mm or less,for example 3 mm to 6 mm, and more preferably 4 mm to 5 mm. When thethickness of the supporting portion is compared to the thickness of thesubstrate, preferably the thickness of the supporting portion is atleast twice the thickness of the substrate.

The substrate support can be configured as a boat where a plurality ofplacing portions extend parallel from the body. The body comprises, forexample, silicon carbide. The supporting portion may be in any shapethat the substrate can be placed on one end face of the portion,including cylinder, elliptic cylinder, and polygonal cylinder. Thesupporting portion preferably has a larger thickness than thickness of aplacing portion of the main body.

A second feature of the invention is thermal treatment apparatus thatperforms heat treatment with a substrate being supported by a substratesupport, wherein the substrate support has a main body portion and asupporting portion which is provided on the main body portion and incontact with the substrate, and the supporting portion is made ofsilicon, and a substrate-placing face of the supporting portion, onwhich the substrate is placed, is coated with a film comprising one or aplural number of materials of silicon carbide (SiC), silicon oxide(SiO₂), silicon nitride (Si₃O₄), glassy carbon, and microcrystallinediamond.

The invention is an invention where the silicon supporting-portionhaving the same hardness or thermal expansion coefficient as thesubstrate is coated with an anti-adhesion film such as silicon carbidefilm, and the objects, constitution, and operation and effects of theinvention are completely different from the aforementioned conventionalexamples described in patent literatures 2 to 5, wherein the supportingportion mainly comprises silicon carbide, and silicon carbide and thelike is coated thereon.

When a silicon carbide film is coated, thickness of the film ispreferably 0.1 μm to 50 μm, more preferably 0.1 μm to 15 μm, and furtherpreferably 0.1 μm to 3 μm.

When the thickness of the silicon supporting-portion and the thicknessof the silicon carbide film are shown in a ratio between the two, thethickness of the silicon carbide film is preferably 0.0025% to 1.25% ofthe thickness of the silicon supporting-portion, more preferably 0.0025%to 0.38%, and further preferably 0.0025% to 0.25%.

For the film coated on the silicon supporting-portion, the siliconnitride (Si₃O₄) can be used in addition to the silicon carbide (SiC).When the silicon nitride film is used, thickness of the film ispreferably 0.1 μm to 30 μm, and more preferably 0.1 μm to 5 μm.

A third feature of the invention is thermal treatment apparatus thatperforms heat treatment with a substrate being supported by thesubstrate support, wherein the substrate support has a main body portionand a supporting portion which is provided on the main body portion andin contact with the substrate, and the supporting portion is made ofsilicon, and a plural number of different films are stacked on asubstrate-placing face of the supporting portion, and hardness of anuppermost film is the lowest in the plural number of films at heattreatment temperature, or the uppermost film is amorphous.

Here, at least one of the plural number of stacked films preferablycomprises a material selected from the silicon carbide (SiC), siliconnitride (SiN), polycrystalline silicon (Poly-Si), silicon oxide (SiO₂),glassy carbon, and microcrystalline diamond. In this way, the materialhaving high heat resistance is stacked on the siliconsupporting-portion, thereby adhesion between the substrate and thesupporting portion can be prevented.

The uppermost surface (face contacting to the substrate) of the pluralnumber of films preferably comprises a material having a lower hardnessthan that of other films during heat treatment, such as silicon oxide(SiO₂).

It is further preferable that material of the uppermost surface hashardness lower than that of other films and lower than that of thesubstrate during heat treatment. The SiO₂ of the uppermost surface ispreferably amorphous.

When two layers are formed as the stacked films, it is preferable thatone of them is a silicon carbide film, and an uppermost film is asilicon oxide film.

The main body portion of the substrate support may comprise siliconcarbide (SiC).

While the substrate support may be a sheet-type one for supporting asingle substrate, it can be configured in a way that a plural number ofsubstrates are supported approximately horizontally with a gap in aplural number of stages.

The thermal treatment apparatus can be used as thermal treatmentapparatus for treating the substrate at high temperature of 1000° C. ormore, in addition, 1350° C. or more.

A fourth feature of the invention is the thermal treatment apparatusthat performs heat treatment with a substrate being supported by asubstrate support, wherein the substrate support has a main body portionand a supporting portion which is provided on the main body portion andin contact with the substrate, and the supporting portion is made ofsilicon, and a silicon carbide (SiC) film is formed on asubstrate-placing face of the supporting portion, and a silicon oxide(SiO₂) film is formed on an uppermost surface.

A fifth feature of the invention is thermal treatment apparatus thatperforms heat treatment with a substrate being supported by a substratesupport, wherein the substrate support has a main body portion and asupporting portion which is provided on the main body portion and incontact with the substrate, and the supporting portion is made ofsilicon, and a coating film is formed on a substrate-placing face of thesupporting portion, and hardness of the coating film is lower thanhardness of the substrate during heat treatment at heat treatmenttemperature, or the coating film is amorphous.

A sixth feature of the invention is a method for manufacturing asubstrate, comprising a process for carrying the substrate into atreatment room; a process for supporting the substrate by a supportingportion formed from a silicon platelike-member having a larger thicknessthan thickness of the substrate; a process for heat-treating thesubstrate in the treatment room with the substrate being supported bythe supporting portion, and a process for carrying out the substratefrom the treatment room.

A seventh feature of the invention is a method for manufacturing asubstrate, comprising a process for carrying the substrate into atreatment room; a process for supporting the substrate by a siliconsupporting-portion wherein a substrate-placing face, on which thesubstrate is placed, is coated with a film comprising one or a pluralnumber of materials of silicon carbide (SiC), silicon oxide (SiO₂),glassy carbon, and microcrystalline diamond; a process for heat-treatingthe substrate in the treatment room with the substrate being supportedby the supporting portion; and a process for carrying out the substratefrom the treatment room.

A eighth feature of the invention is a method for manufacturing asemiconductor device, comprising a process for carrying a substrate intoa treatment room; a process for supporting the substrate by thesupporting portion formed from a silicon platelike-member having alarger thickness than thickness of the substrate; a process forheat-treating the substrate in the treatment room with the substratebeing supported by the supporting portion; and a process for carryingout the substrate from the treatment room.

A ninth feature of the invention is a method for manufacturing asemiconductor device, comprising a process for carrying a substrate intoa treatment room; a process for supporting the substrate by a siliconsupporting-portion wherein a substrate-placing face, on which thesubstrate is placed, is coated with a film comprising one or a pluralnumber of materials of silicon carbide (SiC), silicon oxide (SiO₂),glassy carbon, and microcrystalline diamond; a process for heat-treatingthe substrate in the treatment room with the substrate being supportedby the supporting portion; and a process for carrying out the substratefrom the treatment room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing thermal treatment apparatusaccording to an embodiment of the invention;

FIG. 2 is a cross section view showing a reactor used in the thermaltreatment apparatus according to the embodiment of the invention;

FIG. 3 is a cross section view showing a substrate support used in thethermal treatment apparatus according to the embodiment of theinvention;

FIG. 4 is an expanded section view of the substrate support used in thethermal treatment apparatus according to the embodiment of theinvention;

FIG. 5 is an expanded plan view of the substrate support used in thethermal treatment apparatus according to the embodiment of theinvention;

FIG. 6 is a cross section view showing a first modification of thesubstrate support used in the thermal treatment apparatus according tothe embodiment of the invention;

FIG. 7 shows a second modification of the substrate support used in thethermal treatment apparatus according to the embodiment of theinvention, wherein (a) is a plan view, and (b) is a cross section viewalong a line A-A of (a);

FIG. 8 shows a third modification of the substrate support used in thethermal treatment apparatus according to the embodiment of theinvention, wherein (a) is a plan view, and (b) is a cross section viewalong a line B-B of (a);

FIG. 9 is a cross section view showing a fourth modification of thesubstrate support used in the thermal treatment apparatus according tothe embodiment of the invention;

FIG. 10 is a cross section view showing various modifications of thesupporting portion;

FIG. 11 is a cross section view showing a substrate support used inthermal treatment apparatus according to another embodiment of theinvention; and

FIG. 12 is a diagram showing temperature change during treating asubstrate in the embodiment of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Next, embodiments of the invention are described according to drawings.

FIG. 1 shows thermal treatment apparatus 10 according to an embodimentof the invention. The thermal treatment apparatus 10 is, for example,vertical-type apparatus, and has a chassis 12 in which major parts ofthe apparatus are disposed. The chassis 12 is connected with a pod stage14, and a pod 16 is carried onto the pod stage 14. The pod 16 receives,for example, 25 substrates, and is set on the pod stage 14 with anot-shown cap being closed.

In the chassis 12, a pod-carrying device 18 is disposed at a positionopposed to the pod stage 14. Near the pod-carrying device 18, a podshelf 20, a pod opener 22, and a sensor 24 of the number of substratesare disposed. The pod-carrying device 18 carries the pod 16 among thepod stage 14, pod shelf 20 and pod opener 22. The pod opener 22 is foropening the cap of the pod 16, and the number of substrates in the pod16 with the cap being opened is sensed by the sensor 24 of the number ofsubstrates.

Furthermore, a substrate transfer device 26, notch aligner 28 andsubstrate support 30 (boat) are disposed in the chassis 12. Thesubstrate transfer device 26 has an arm 32 which can take out, forexample, five substrates, and the substrates are carried among the podplaced at a position of the pod opener 22, notch aligner 28 andsubstrate support 30 by moving the arm 32. The notch aligner 28 detectsa notch or an orientation-flat formed in the substrate, and arranges thenotch or the orientation-flat in the substrate to a regular position.

FIG. 2 shows a reactor 40. The reactor 40 has a reactor tube 42, and asubstrate support 30 is inserted into the reactor tube 42. A bottom areaof the reactor tube 42 is opened for inserting the substrate support 30,and the opened area is sealed by a seal cap 44. Periphery of the reactortube 42 is covered by a soaking tube 46, and a heater 48 is disposedaround the soaking tube 46. A thermocouple 50 is disposed between thereactor tube 42 and the soaking tube 46, so that temperature in thereactor 40 can be monitored. The reactor tube 42 is connected with aintroduction tube 52 for introducing treatment gas and an exhaust pipe54 for exhausting the treatment gas.

Next, operation of the thermal treatment apparatus 10 configured asabove is described.

First, when the pod 16 which has received a plural number of substratesis set on the pod stage 14, the pod 16 is carried from the pod stage 14to the pod shelf 20 by the pod-carrying device 18, and stocked in thepod shelf 20. Next, the pod 16 stocked in the pod shelf 20 is carriedand set onto the pod opener 22 by the pod-carrying device 18, and thecap of the pod 16 is opened by the pod opener 22, and then the number ofsubstrates received in the pod 16 is sensed by the sensor 24 of thenumber of substrates.

Next, a substrate is taken out from the pod 16 located at a position ofthe pod opener 22 by the substrate transfer device 26, and transferredto the notch aligner 28. In the notch aligner 28, the notch is detectedwith the substrate being rotated, and the notches in the substrates arealigned to a fixed position according to the detected data. Next, thesubstrates are taken out from the notch aligner 28 by the substratetransfer device 26 and transferred to the substrate support 30.

In this way, after one batch of substrates are transferred to thesubstrate support 30, the substrate support 30 loaded with thesubstrates is charged into the reactor 40 in which temperature has beenset to, for example, 700° C., and then the reactor tube 42 is sealed bythe seal cap 44. Next, furnace temperature is increased to heattreatment temperature, and then the treatment gas is introduced throughthe introduction tube 52. The treatment gas includes nitrogen, argon,hydrogen, and oxygen. When the substrate is heat-treated, the substrateis heated to, for example, about 1000° C. or more. In this period, theheat treatment of the substrate is performed according to previouslyestablished programs of heating and heat treatment with monitoringtemperature in the reactor tube 42 using the thermocouple 50.

When the heat treatment of the substrate is finished, the furnacetemperature is lowered to about 700° C., and then the substrate support30 is unloaded from the reactor 40, and the substrate support 30 is madeto wait at a predetermined position until all substrates supported bythe substrate support 30 are cooled. Again in lowering the furnacetemperature, the cooling is performed according to a previouslyestablished cooling program with monitoring the temperature in thereactor tube 42 using the thermocouple 50. Next, when the substrateswaiting in the substrate support 30 are cooled to the predeterminedtemperature, the substrates are taken out from the substrate support 30by the substrate transfer device 26, and carried and received into anempty pod 16 set on the pod opener 22. Next, the pod 16 receiving thesubstrates are carried into the pod shelf 20 by the pod transfer device18, and finally transferred onto the pod stage 14.

Next, the substrate support 30 is described in detail.

In FIG. 3 to FIG. 5, the substrate support 30 is formed from a main bodyportion 56 and a supporting portion 58. The main body portion 56comprises, for example, silicon carbide, and has an upper plate 60, alower plate 62, and a pole 64 for connecting between the upper plate 60and the lower plate 62. In the main body portion 56, a plurality ofplacing portions 66 extending from the pole 64 to a side of thesubstrate transfer device 26 are formed parallel.

The supporting portion 58 comprises a silicon platelike-member, and isformed in the shape of a cylinder concentric with a substrate 68, andthe supporting portion 58 is placed on the placing portion 66 in acondition that a bottom of the supporting portion 58 is in contact witha top of the placing portion 66, and the substrate 68 is placed andsupported on the supporting portion 58 in a condition that a bottom ofthe substrate 68 is in contact with a top of the supporting portion 58.

The supporting portion 58 has a smaller diameter than diameter of thesubstrate 68, that is, the top of the supporting portion 58 has asmaller area than an area of a flat face as the bottom of the substrate68, and the substrate 68 is supported by the supporting portion 58 withperiphery of the substrate 68 being left. Diameter of the substrate 68is, for example, 300 mm, therefore diameter of the supporting portion 58is less than 300 mm, and preferably about 100 mm to 250 mm (about ⅓ to ⅚of outer diameter of the substrate).

The diameter (area) of the supporting portion 58 can be larger than thediameter (area) of the substrate 68. In this case, thickness of thesupporting portion 58 is preferably increased.

Thickness in a cylinder-axis direction of the supporting portion 58 isformed larger than thickness of the substrate 68. The thickness of thesubstrate 68 is, for example, 700 μm, therefore the thickness of thesupporting portion 58 is more than 700 μm, and may be 10 mm at maximum,and preferably twice the thickness of the substrate 68 or more, forexample 3 mm to 10 mm, more preferably 3 mm to 6 mm, and furtherpreferably 4 mm to 5 mm. The thickness of the supporting portion 58 islarger than the thickness of the placing portion 66. The reason formaking the thickness of the substrate 68 to be such thickness is toincrease rigidness of the supporting portion 58 itself and suppressdeformation of the supporting portion 58 during heat treatment.

If the deformation during heat treatment can be suppressed, thethickness of the silicon supporting-portion 58 is not necessarily formedto be larger than thickness of the substrate 68.

As shown in FIG. 6, it is acceptable that a circular fitting groove 74is formed in the placing portion 66 corresponding to the supportingportion 58, and the supporting portion 58 is fitted in the fittinggroove 74. The total thickness of the supporting portion 58 and theplacing portion 66 can be reduced without reducing the thickness of thesupporting portion 58, thereby the number of substrates 68 to be treatedat a time can be increased. In addition, the supporting portion 58 isfitted in the fitting groove 74, thereby a position of the supportingportion 58 can be stabilized. In this case, a slight gap may be formedbetween the supporting portion 58 and the fitting groove 74 inconsideration of thermal expansion.

Moreover, as shown in FIG. 7, it is acceptable that an opening 66 a isprovided in the placing portion 66, a convex portion 58 a fitted in theopening 66 a is provided on the bottom of the supporting portion 58, andthe convex portion 58 a on the supporting portion 58 is fitted in theopening 66 a in the placing portion 66. In the invention, a memberhaving such a shape is assumed to be included in the platelike member.Again in this case, it is better that the slight gap is formed betweenthe convex portion 58 a on the supporting portion 58 and the opening 66a in the placing portion 66 in consideration of thermal expansion.

The shape of the supporting portion 58 need not be cylindrical unlikethe embodiment, and can be configured as an elliptic cylinder or apolygonal cylinder. The supporting portion 58 can be fixed to theplacing portion 66.

An anti-adhesion layer (coated film) 70 is formed on the top(substrate-placing face) of the supporting portion 58 at a side of thesubstrate 68. The anti-adhesion layer 70 comprises a material havingexcellent heat resistance and wear resistance, including a siliconnitride (Si₃N₄) film, a silicon carbide (SiC) film, a silicon oxide(SiO₂) film, glassy carbon, and microcrystalline diamond, which areformed by surface treatment of the silicon, or by depositing thematerial on the surface of the silicon using CVD (plasma CVD or thermalCVD) and the like, so that adhesion between the supporting portion 58and the substrate 68 is prevented after treatment of the substrate 68.When the anti-adhesion layer 70 comprises the silicon carbide (SiC)film, thickness of the film is preferably in a range of 0.1 μm to 50 μm.When the thickness of the silicon carbide film 70 is increased, thesilicon supporting-portion 58 is stretched by the silicon carbide film70 due to difference in coefficients of thermal expansion betweensilicon and silicon carbide, thereby deformation level of the supportingportion as a whole becomes large, and slip may occur in the substrate 68due to the large deformation. On the contrary, when the silicon carbidefilm 70 has the thickness as above, the stretched level of the siliconsupporting-portion 58 by the silicon carbide film 70 is reduced,resulting in decrease in deformation level of the supporting portion asa whole. That is, when the thickness of the silicon carbide film 70 isdecreased, stress due to the difference in coefficients of thermalexpansion between the supporting portion 58 and the film 70 is reduced,and the deformation level of the supporting portion as a whole isreduced, in addition, the thermal expansion coefficient of thesupporting portion as a whole approaches the original thermal expansioncoefficient of silicon (approximately equal thermal expansioncoefficient of the substrate 68 when the substrate comprises silicon),and consequently occurrence of the slip can be prevented.

When the thickness of the silicon carbide film 70 is less than 0.1 μm,the silicon carbide film 70 wears because of excessively small thicknessof the film, therefore the silicon carbide needs to be recoated on thesilicon supporting-portion 58, and one supporting portion 58 can not berepeatedly used. When the thickness of the silicon carbide film 70 is0.1 μm or more, the silicon carbide film 70 need not be frequentlyrecoated on the silicon supporting-portion 58, and one supportingportion 58 can be repeatedly used. The silicon carbide film 70 having athickness of 1 μm or more is preferable, because the wear of the film isfurther reduced, and the number of repeatable use of one supportingportion 58 is further increased.

When the thickness of the silicon carbide film 70 is more than 50 μm,the silicon carbide film 70 itself is easily cracked, and the slip iseasy to occur in the substance due to the crack. When the thickness ofthe film 70 is 50 μm or less, the crack in the film 70 is hard to occur,and the stress due to the difference in coefficients of thermalexpansion between the silicon supporting-portion 58 and the siliconcarbide film 70 is reduced as above, therefore the deformation of thesupporting portion as a whole is reduced, consequently the occurrence ofthe slip in the substrate can be prevented. When the thickness of thesilicon carbide film is 15 μm or less, the slip in the substrate is hardto occur. Furthermore, when the thickness of the silicon carbide film 70is 0.1 μm to 3 μm, the slip in the substrate 68 does not occur.Accordingly, the thickness of the silicon carbide film 70 is preferably0.1 μm to 50 μm, more preferably 0.1 μm to 15 μm, and further preferably0.1 μm to 3 μm.

When the thickness of the silicon supporting-portion 58 and thethickness of the silicon carbide film 70 are shown in a ratio betweenthe two, the thickness of the silicon carbide film 70 is preferably0.0025% to 1.25% of the thickness of the silicon supporting-portion 58,more preferably 0.0025% to 0.38%, and further preferably 0.0025% to0.25%.

The film 70 can be also formed by coating the silicon nitride (Si₃N₄) inaddition to the silicon carbide using the plasma CVD or the thermal CVD.When the film is formed from the silicon nitride, the thickness of thefilm 70 is preferably 0.1 μm to 30 μm, and more preferably 0.1 μm to 5μm.

Periphery of the top of the supporting portion 58 is smoothly chamferedand thus a concave portion 72 is formed. The concave portion 72 preventsproduction of flaw and the like in the substrate 68 by the substrate 68contacting to the periphery of the supporting portion 58.

Although the anti-adhesion layer 70 is formed on the entire surface ofthe supporting portion 58, as shown in FIG. 8, it is acceptable thatchips 76 comprising those materials are placed on a part of thesubstrate-placing face of the supporting portion 58, and the substrate68 is supported by the chips 76. In this case, three chips 76 or moreare preferably provided.

As shown in FIG. 9, a concentric groove 78 is formed near the peripheryof the supporting portion 58 to decrease an area contacting to thesubstrate 68, thereby possibility of the flaw produced by the substrate68 contacting to the supporting portion 58 can be reduced, and shift ofthe substrate 68 can be prevented.

In the embodiment, since the thickness of the supporting portion 58 is apredetermined thickness larger than the thickness of the substrate 68 asabove, rigidness of the supporting portion 58 can be increased, thedeformation of the supporting portion 58 with temperature change duringcarrying-in of the substrate, heating, cooling, heat treatment,carrying-out of the substrate and the like can be suppressed.Accordingly, the slip occurring in the substrate 68 due to thedeformation of the supporting portion 58 can be prevented. Moreover,since the material of the supporting portion 58 is made of silicon thatis the same material as the substrate 68, that is, since a materialhaving the same thermal expansion coefficient or hardness as thesubstrate 68 made of silicon is used, difference in thermal expansion orthermal contraction between the substrate 68 and the supporting portion58 with temperature change can be eliminated, and even if stress isgenerated at a contact point between the substrate 68 and the supportingportion 58, the stress is easily released, therefore the substrate 68 ishardly flawed. Accordingly, the slip occurring in the substrate 68 dueto the difference in coefficients of thermal expansion or hardnessbetween the substrate 68 and the supporting portion 58 can be prevented.

While a case that the diameter (area) of the supporting portion issmaller than that of the substrate was described in the embodiment andexample, the diameter of the supporting portion can be larger than thatof the substrate. In this case, the thickness of the supporting portion58 needs to be further increased to secure the rigidness of thesupporting portion 58.

Since the supporting portion 58 is coated with the anti-adhesion film 70such as silicon carbide film, adhesion due to heat generated between thesupporting portion 58 and the substrate 68 can be prevented. Since thefilm 70 is formed to have small thickness as above, the stress due tothe difference in coefficients of thermal expansion between thesupporting portion 58 and the film 70 can be reduced, and the thermalexpansion coefficient of the entire supporting portion including thefilm 70 can be maintained to be approximately equal to the originalthermal expansion coefficient of silicon without having an adverseinfluence upon the thermal expansion coefficient of the siliconsupporting-portion 58. The film 70 may be coated on a back or sides ofthe supporting portion 58.

In FIG. 10, various modifications on the supporting portion 58 areshown.

Although the film 70 was formed only on the substrate-placing face ofthe supporting portion 58 in the above embodiment, as shown in FIG. 10(a), the film 70 may be formed on the supporting portion 58 as a whole,that is, it may be formed on the front (substrate-placing face), sidesand back of the supporting portion 58.

As shown in FIG. 10( b), the film 70 can be formed on the front(substrate-placing face) and sides of the supporting portion 58 exceptfor the back of the supporting portion 58.

Moreover, the film 70 is not limited to a single layer, and may beformed as multiple layers, for example as shown in FIG. 10(C), a secondfilm 82 can be formed on a first film 80. The first film 80 comprises,for example, the silicon carbide (SiC), silicon nitride (Si₃N₄),polycrystalline silicon (Poly-Si), silicon oxide (SiO₂), glassy carbon,or microcrystalline diamond. When the film is formed from the siliconcarbide or the silicon nitride, it can be formed using the plasma CVD orthe thermal CVD as described before. The second film 82 can be formedfrom a material having lower hardness than that of the first film 70during heat treatment, for example, silicon oxide (SiO₂). Thus, thesecond film 82 that is the uppermost surface comprises the materialhaving the lower hardness than that of the first film 70 during heattreatment, thereby when the stress is generated at the contact pointbetween the substrate 68 and the supporting portion 58 duringhigh-temperature heat treatment, the stress is easily released,therefore the substrate 68 is hardly flawed, consequently the slip ishard to occur. In particular, when the uppermost film 70 comprises SiO₂having lower hardness than that of the substrate (Si) 68 during heattreatment, the SiO₂ having the lower hardness is broken and thus thestress is released during the heat treatment, therefore the substrate 68having the higher hardness is not flawed, and the slip does not occur.That is, it is further preferable that the uppermost surface comprises amaterial having hardness lower than that of other films and lower thanthat of the substrate during heat treatment.

The uppermost SiO₂ is preferably amorphous. The substrate 68 and thesupporting portion 58 are fused at the contact point between them athigh temperature, and when the contact point between the substrate 68and the supporting portion 58 is crystalline at that time, since thecrystalline portion does not flow viscously, the stress due to thedifference between coefficients of thermal expansion can not bereleased, and finally the slip occurs in either the substrate 68 or thesupporting portion 58. On the contrary, when the contact point betweenthe supporting portion 58 and the substrate 68 is amorphous, since theamorphous portion flows viscously, even if the substrate 68 and thesupporting portion 58 are fused, the stress generated at the contactpoint can be released, and the substrate 68 is not flawed, and theoccurrence of the slip can be prevented.

As shown in FIG. 10( d), it is better that the supporting portion 58 iscut out with the periphery of the substrate-placing face of thesupporting portion 58 being left, and formed from the cut-out portion 84formed circularly at a center side and a projection portion 86 formedannularly at the periphery, and the first film 80 and the second film 82are formed on the substrate-placing face and the sides of the projectionportion 86. Accordingly, an area contacted with the substrate 68 can bereduced.

While the second film 82 can be formed using the CVD and the likesimilarly as the first film 80, it may be formed naturally when thesubstrate 68 is treated as described later.

First Example

FIG. 11 shows a first example according to the invention. In thesubstrate support 30 having the body portion comprising, for example,silicon carbide as the above embodiment, the placing portions 66 areformed protrusively from and parallel to the pole 64. Multiple poles,for example, three to four poles are provided as the pole 64. A plate(base) 88 comprises a cylindrical platelike-member made of, for example,silicon carbide (SiC), and a bottom periphery of the plate 88 issupported by the placing portion 66. The supporting portion 82 comprisesa cylindrical platelike member made of silicon (Si), and placed on a topof the plate 88. The anti-adhesion layer 70 comprising, for example,silicon carbide is formed on the top of the supporting portion 82. Theanti-adhesion layer 70 is preferably 0.1 μm to 50 μm thick. Thesubstrate 68 is supported by the supporting portion 82 via theanti-adhesion layer 70.

While thickness of the plate 88 and thickness of the supporting portion82 are preferably larger than the thickness of the substrate 68respectively, only the thickness of the supporting portion 82 may belarger than the thickness of the substrate 68.

The plate 88 was 308 mm in diameter Φ and 3 mm in thickness. Thesupporting portion 82 was 200 mm in diameter Φ and 4 mm in thickness.The substrate 68 is a silicon wafer having a diameter Φ of 300 mm and athickness of 700 μm. The anti-adhesion layer 70 comprising siliconcarbide was 0.1 μm to 50 μm thick. In heat treatment, the substrate 68supported by the substrate support 30 was loaded into a reactor held ata temperature of 600° C., and after loading the substrate, an inside ofthe reactor was heated to 1200° C. or 1350° C. as treatment temperature,and then nitrogen (N₂) gas and oxygen (O₂) gas were introduced and theinside of the reactor was maintained at the treatment temperature for apredetermined time, and then the reactor temperature was cooled to 600°C. and the substrate 68 supported by the substrate support 30 wasunloaded. The heating or cooling was performed in multiple steps suchthat the heating or cooling rate of the substrate 68 was decreased withtemperature increase. The reason why the heating or cooling wasperformed in the multiple steps in this way (the reason why the heatingor cooling rate was decreased with temperature increase) is because iftemperature is suddenly changed at high temperature, the temperature isnot changed uniformly in a substrate plane, causing the slip. The heattreatment time was about 13 to 14 hours in total. As a result, the slipoccurring in the substrate 68 was not found in both cases of thetreatment temperature of 1200° C. and 1350° C.

Second Example

FIG. 12 shows a second example according to the invention. In thesubstrate support 30 having the body portion comprising, for example,the silicon carbide similarly as the above embodiment, placing portions66 are formed protrusively from and parallel to the pole 64. Themultiple poles, for example, three to four poles are provided as thepole 64. The plate (base) 88 comprises the cylindrical platelike-membermade of, for example, silicon carbide (SiC), and the bottom periphery ofthe plate 88 is supported by the placing portion 66. The supportingportion 58 made of silicon (Si) comprising the cylindricalplatelike-member is placed on the plate 88. The anti-adhesion layer 70comprising, for example, silicon carbide is formed on a top of thesupporting portion 58.

The silicon carbide plate 88 having a thickness of 2.5 mm to 3 mm and adiameter Φ of 308 mm was supported by the substrate support 30 havingthe body portion made of silicon carbide, and the siliconsupporting-portion 58 having a thickness of 4 mm and a diameter Φ of 200mm, whose substrate-placing face is coated with the silicon carbide film70 as the anti-adhesion layer, was placed thereon, and the substrate 68that was a silicon wafer having a thickness of 700 μm and a diameter Φof 300 mm was placed thereon. In the heat treatment, as shown in FIG.12, the substrate 68 supported by the substrate support 30 was loadedinto the reactor held at a temperature of 600° C., and after loading thesubstrate, the inside of the reactor was heated to 1350° C. while thetreatment temperature at a heating rate was stepwise changed, and thenthe nitrogen (N₂) gas and the oxygen (O₂) gas were introduced and theinside of the reactor was maintained at the treatment temperature for apredetermined time, and then reactor temperature was cooled to 600° C.at a cooling rate which was stepwise changed and the substrate 68supported by the substrate support 30 was unloaded. The heating orcooling rate of the substrate 68 was decreased with temperatureincrease. That is, the heating rate was set such that a heating ratefrom 600° C. to 1000° C. was lower than a heating rate from the roomtemperature to 600° C., a heating rate from 1000° C. to 1200° C. waslower than the heating rate from 600° C. to 1000° C., and a heating ratefrom 1200° C. to 1350° C. was lower than the heating rate from 1000° C.to 1200° C. Conversely, the cooling rate was set such that a coolingrate from 1350° C. to 1200° C. was lower than a cooling rate from the1200° C. to 1000° C., the cooling rate from 1200° C. to 1000° C. waslower than a cooling rate from 1000° C. to 600° C., and the cooling ratefrom 1000° C. to 600° C. was lower than a cooling rate from 600° C. tothe room temperature. The reason why the heating or cooling wasperformed in the multiple steps in this way (the reason why the heatingor cooling rate was decreased with temperature increase) is because iftemperature is suddenly changed at high temperature, the temperature isnot changed uniformly in the substrate plane, causing the slip. The heattreatment time was about 13 to 14 hours in total. As a result, when thesilicon carbide film 70 was 0.1 μm to 3 μm thick, the slip did not occurin the substrate 68. When the film 70 was 15 μm or 50 μm thick, the slipwas hard to occur in the substrate 68.

The example was repeated, as a result it was found that the slip washard to occur in and after the second evaluation compared with the firstevaluation. It is considered that this is because an amorphous SiO₂ filmis formed on a surface of the film 70 on the supporting portion 58 inthe heat treatment at a N₂ or O₂ atmosphere in the first evaluation. Theamorphous SiO₂ film is formed on the uppermost surface of the supportingportion 58, thereby hardness of the contact portion between thesupporting portion 58 and the substrate 68 is lowered during heattreatment compared with the film 70 made of SiC or the substrate 68 madeof Si, and even if stress is generated at the contact point between thesubstrate 68 and the supporting portion 58 during the high-temperatureheat treatment, the stress can be released. Moreover, since the SiO₂ isamorphous, even if the substrate 68 and the supporting portion 58 arefused at the contact point between them during the high-temperature heattreatment, the stress generated at the contact point, which was fuseddue to viscous flowing of an amorphous portion, can be released byviscous flowing (viscous deformation) of the amorphous SiO₂. As aresult, it is considered that the flaw produced in the substrate 68during the high-temperature heat treatment in and after the secondevaluation can be suppressed, and thus the slip occurring in thesubstrate 68 can be suppressed.

While a case that the amorphous SiO₂ film was formed on the surface ofthe film 70 made of SiC provided on the top of the supporting portion 58made of Si was described in the example, it is appreciated that theamorphous SiO₂ may be applied directly on the surface of the supportingportion 58 made of Si.

While batch-type apparatus for heat-treating a plural number ofsubstrates was used as the thermal treatment apparatus in thedescription of the embodiments and examples, the apparatus is notlimited to this, and may be sheet-type apparatus.

The thermal treatment apparatus of the invention can be applied to amanufacturing process of the substrate.

An example that the thermal treatment apparatus of the invention isapplied to one step of a manufacturing process of a SIMOX (Separation byImplanted Oxygen) wafer which is one of SOI (Silicon On Insulator)wafers is described.

First, ion implantation of oxygen ions is performed into asingle-crystal silicon wafer using ion implantation apparatus and thelike. Then, the wafer into which the oxygen ions have been implanted isannealed at a high temperature of 1300° C. to 1400° C., for example1350° C. or more, in an atmosphere of, for example, Ar or O₂ using thethermal treatment apparatus in the above embodiments. A SIMOX waferhaving a SiO₂ layer formed within the wafer (embedded SiO₂ layer) isprepared by performing these treatments.

In addition to the SIMOX wafer, the thermal treatment apparatus of theinvention can be applied to one step of a manufacturing process of ahydrogen annealing wafer. In this case, the wafer is annealed at ahigh-temperature of 1200° C. or more in a hydrogen atmosphere using thethermal treatment apparatus of the invention. Accordingly, crystaldefects in a wafer surface layer where IC (Integrated Circuit) isproduced can be reduced, and crystal integrity can be improved.

In addition to this, the thermal treatment apparatus of the inventioncan be applied to one step of a manufacturing process of an epitaxialwafer.

Even in a case that the high-temperature annealing is performed as onestep in the manufacturing processes of the substrates as above, the slipoccurring in the substrate can be prevented by using the thermaltreatment apparatus of the invention.

In addition, the thermal treatment apparatus of the invention can beapplied to a manufacturing process of a semiconductor device.

In particular, the apparatus is preferably applied to a thermaltreatment process performed at a relatively high temperature, forexample, a thermal oxidation process such as wet oxidation, dryoxidation, hydrogen combustion oxidation (pyrogenic oxidation), and HCloxidation, or a thermal diffusion process for diffusing an impurity(dopant) such as boron (B), phosphorous (P), arsenal (As), and antimony(Sb) into a semiconductor thin film.

Even in a case that such a heat treatment process is performed as onestep in the manufacturing process of the semiconductor device,occurrence of the slip can be prevented by using the thermal treatmentapparatus of the invention.

As above, the invention is characterized in the matters described inclaims, and the invention further includes the following embodiments.

(1) The thermal treatment apparatus according to claim 1, whereinthickness of the supporting portion is at least twice the thickness ofthe substrate.

(2) The thermal treatment apparatus according to claim 1, wherein thebody portion has a placing portion for placing the supporting portion,and thickness of the supporting portion is larger than thickness of theplacing portion.

(3) The thermal treatment apparatus according to claim 1, wherein thesupporting portion has a substrate-placing face, on which the substrateis placed, and one or a plural number of materials of silicon nitride(Si₃N₄), silicon carbide (SiC), silicon oxide (SiO₂), glassy carbon, andmicrocrystalline diamond is/are coated on the substrate-placing face.

(4) The thermal treatment apparatus according to claim 1, wherein thesupporting portion has the substrate-placing face, on which thesubstrate is placed, and one or a plural number of chip/chips comprisingone or a plural number of materials of silicon nitride (Si₃N₄), siliconcarbide (SiC), silicon oxide (SiO₂), glassy carbon, and microcrystallinediamond is/are provided on the substrate-placing face.

(5) The thermal treatment apparatus according to claim 1, wherein thesupporting portion has the substrate-placing face, on which thesubstrate is placed, and a concave portion or a groove concentric withthe substrate is formed on the substrate-placing face.

(6) The thermal treatment apparatus according to claim 1, wherein thesupporting portion has the substrate-placing face, on which thesubstrate is placed, and the concave portion or the groove concentricwith the substrate is formed on periphery of the substrate-placing face.

(7) The thermal treatment apparatus according to claim 1, wherein themain body has the placing portion for placing the supporting portion,and a fitting groove in which the supporting portion is fitted is formedin the placing portion.

(8) The thermal treatment apparatus according to claim 1, wherein themain body has the placing portion for placing the supporting portion,and an opening or a groove is formed in the placing portion, a convexportion which is fitted in the opening or the groove is formed on thesupporting portion, and the convex portion on the supporting portion isfitted in the opening or the groove.

(9) The thermal treatment apparatus according to claim 1, wherein anarea of the substrate-placing face of the supporting portion is smallerthan an area of a flat face of the substrate.

(10) The thermal treatment apparatus according to claim 1, wherein thesupporting portion is cylindrical, and the diameter of the supportingportion is smaller than the diameter of the substrate.

(11) The thermal treatment apparatus according to claim 6, wherein thethickness of the silicon carbide film is 0.0025% to 1.25% of thethickness of the supporting portion.

(12) The thermal treatment apparatus according to claim 6, wherein thethickness of the silicon carbide film is 0.0025% to 0.38% of thethickness of the supporting portion.

(13) The thermal treatment apparatus according to claim 6, wherein thethickness of the silicon carbide film is 0.0025% to 0.25% of thethickness of the supporting portion.

(14) The thermal treatment apparatus according to claim 6, wherein asilicon oxide (SiO₂) film is formed on an uppermost face of thesupporting portion.

(15) The thermal treatment apparatus according to claim 10, wherein theplural number of films comprise two types of films, and one of them is asilicon carbide (SiC) film, and an uppermost film is a silicon oxide(SiO₂) film.

(16) The thermal treatment apparatus according to claim 1, wherein acomposition of the body portion is silicon carbide (SiC).

(17) The thermal treatment apparatus according to claim 1, wherein thesubstrate support is configured such that a plural number of substratesare supported approximately horizontally with a gap in a plural numberof stages.

(18) The thermal treatment apparatus according to claim 1, wherein theheat treatment is performed at a temperature of 1000° C. or more.

(19) The thermal treatment apparatus according to claim 1, wherein theheat treatment is performed at a temperature of 1350° C. or more.

(20) A method for treating a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a supporting portion formed from a silicon platelike-memberhaving a thickness larger than the thickness of the substrate; a processfor heat-treating the substrate in the treatment room with the substratebeing supported by the supporting portion; and a process for carryingout the substrate from the treatment room.

(21) A method for treating a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a substrate-placingface, on which the substrate is placed, is coated with a film comprisingone or a plural number of materials of silicon carbide (SiC), siliconoxide (SiO₂), glassy carbon, and microcrystalline diamond; a process forheat-treating the substrate in the treatment room with the substratebeing supported by the supporting portion; and a process for carryingout the substrate from the treatment room.

(22) A method for manufacturing a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a plural number ofdifferent films are stacked on a substrate-placing face, on which thesubstrate is placed, and the hardness of an uppermost film is the lowestin the plural number of films at heat treatment temperature, or theuppermost film is amorphous; a process for heat-treating the substratein the treatment room with the substrate being supported by thesupporting portion; and a process for carrying out the substrate fromthe treatment room.

(23) A method for manufacturing a semiconductor device, comprising aprocess for carrying a substrate into a treatment room; a process forsupporting the substrate by a silicon supporting-portion wherein aplural number of different films are stacked on a substrate-placingface, on which the substrate is placed, and the hardness of an uppermostfilm is the lowest in the plural number of films at heat treatmenttemperature, or the uppermost film is amorphous; a process forheat-treating the substrate in the treatment room with the substratebeing supported by the supporting portion; and a process for carryingout the substrate from the treatment room.

(24) A method for treating a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a plural number ofdifferent films are stacked on a substrate-placing face, on which thesubstrate is placed, and the hardness of an uppermost film is the lowestin the plural number of films at heat treatment temperature, or theuppermost film is amorphous; a process for heat-treating the substratein the treatment room with the substrate being supported by thesupporting portion; and a process for carrying out the substrate fromthe treatment room.

(25) A method for manufacturing a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a silicon carbide(SiC) film is formed on a substrate-placing face, on which the substrateis placed, in addition, a silicon oxide (SiO₂) film is formed on anuppermost face; a process for heat-treating the substrate in thetreatment room with the substrate being supported by the supportingportion; and a process for carrying out the substrate from the treatmentroom.

(26) A method for manufacturing a semiconductor device, comprising aprocess for carrying a substrate into a treatment room; a process forsupporting the substrate by a silicon supporting-portion wherein asilicon carbide (SiC) film is formed on a substrate-placing face, onwhich the substrate is placed, in addition, a silicon oxide (SiO₂) filmis formed on an uppermost face; a process for heat-treating thesubstrate in the treatment room with the substrate being supported bythe supporting portion; and a process for carrying out the substratefrom the treatment room.

(27) A method for treating a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a silicon carbide(SiC) film is formed on a substrate-placing face, on which the substrateis placed, in addition, a silicon oxide (SiO₂) film is formed on anuppermost face; a process for heat-treating the substrate in thetreatment room with the substrate being supported by the supportingportion; and a process for carrying out the substrate from the treatmentroom.

(28) A method for manufacturing a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a coating film isformed on a substrate-placing face, on which the substrate is placed,and the hardness of the coating film is lower than the hardness of thesubstrate during heat treatment at heat treatment temperature, or thecoating film is amorphous; a process for heat-treating the substrate inthe treatment room with the substrate being supported by the supportingportion; and a process for carrying out the substrate from the treatmentroom.

(29) A method for manufacturing a semiconductor device, comprising aprocess for carrying a substrate into a treatment room; a process forsupporting the substrate by a silicon supporting-portion wherein acoating film is formed on a substrate-placing face, on which thesubstrate is placed, and the hardness of the coating film is lower thanthe hardness of the substrate during heat treatment at heat treatmenttemperature, or the coating film is amorphous; a process forheat-treating the substrate in the treatment room with the substratebeing supported by the supporting portion; and a process for carryingout the substrate from the treatment room.

(30) A method for treating a substrate, comprising a process forcarrying a substrate into a treatment room; a process for supporting thesubstrate by a silicon supporting-portion wherein a coating film isformed on a substrate-placing face, on which the substrate is placed,and the hardness of the coating film is lower than the hardness of thesubstrate during heat treatment at heat treatment temperature, or thecoating film is amorphous; a process for heat-treating the substrate inthe treatment room with the substrate being supported by the supportingportion; and a process for carrying out the substrate from the treatmentroom.

As described hereinbefore, according to the invention, since thesubstrate is supported by the supporting portion formed from the siliconplatelike-member having a thickness larger than the thickness of thesubstrate, the slip dislocation occurring in the substrate can beprevented.

Moreover, according to the invention, since the siliconsupporting-portion is coated with the anti-adhesion layer such assilicon carbide film, silicon nitride film, or silicon oxide film, theslip occurring in the substrate can be prevented, and the adhesionbetween the heat-treated substrate and the supporting portion can beprevented. Moreover, the hardness of the film coated on thesubstrate-placing face of the supporting portion is lower than thehardness of the substrate during heat treatment in the heat treatment,or the coated film is made amorphous, therefore the slip occurring inthe substrate can be further prevented. Moreover, when a plural numberof films are coated on the substrate-placing face of the supportingportion, the hardness of the uppermost film is the lowest during heattreatment, or the uppermost film is amorphous, therefore, again in thiscase, the slip occurring in the substrate can be further prevented.

INDUSTRIAL APPLICABILITY

The invention can be used for thermal treatment apparatus, a method formanufacturing a semiconductor device, and a method for manufacturing asubstrate, wherein the occurrence of slip dislocation in a substrateduring heat treatment is reduced, and a high-quality semiconductordevice can be manufactured.

1. A thermal treatment method comprising: carrying a substrate into afurnace; heat-treating the substrate by using an oxygen in the furnacewith the substrate being supported by a supporting portion formed from asilicon plate-like member, a substrate-placing face of the supportingportion, on which the substrate is placed, is coated with an amorphoussilicon oxide film; and carrying the heat-treated substrate out of thefurnace, wherein the amorphous silicon oxide film coating thesubstrate-placing face of the supporting portion is formed by theheat-treating.
 2. A thermal treatment method according to claim 1,wherein a thickness of the supporting portion is not less than twice athickness of the substrate and not more than 10 mm, a diameter of thesupporting portion is smaller than a diameter of the substrate.
 3. Athermal treatment method according to claim 2, wherein the thickness ofthe supporting portion is from 3 mm to 10 mm.
 4. A thermal treatmentmethod according to claim 2, wherein the diameter of the supportingportion is from ⅓ to ⅚ of the diameter of the substrate.
 5. A thermaltreatment method according to claim 2, wherein the diameter of thesupporting portion is ⅔ of the diameter of the substrate.
 6. A thermaltreatment method according to claim 2, wherein the heat-treating isperformed with the supporting portion being supported by a main bodyportion formed from a silicon carbide in the furnace.
 7. A thermaltreatment method according to claim 2, wherein the heat-treating isperformed with the supporting portion being supported by a plate, theplate is supported by a main body portion, a diameter of the plate islarger than a diameter of the supporting portion in the furnace.
 8. Athermal treatment method according to claim 2, wherein the heat-treatingis performed with the supporting portion being supported by a plateformed from a silicon carbide, the plate is supported by a main bodyportion formed from a silicon carbide, a diameter of the plate is largerthan a diameter of the supporting portion in the furnace.
 9. A methodfor manufacturing a substrate, comprising: carrying a substrate into afurnace; heat-treating the substrate by using an oxygen in the furnacewith the substrate being supported by a supporting portion formed from asilicon plate-like member, a substrate-placing face of the supportingportion, on which the substrate is placed, is coated with an amorphoussilicon oxide film, a thickness of the supporting portion is not lessthan twice a thickness of the substrate and not more than 10 mm, adiameter of the supporting portion is smaller than a diameter of thesubstrate; and carrying the heat-treated substrate out of the furnace,wherein the amorphous silicon oxide film coating the substrate-placingface of the supporting portion is formed by the heat-treating.
 10. Amethod for manufacturing a SIMOX substrate, comprising: implantingoxygen ions into a substrate; and heat-treating the substrate into whichthe oxygen ions have been implanted in an oxygen atmosphere with thesubstrate being supported by a supporting portion formed from a siliconplate-like member, a substrate-placing face of the supporting portion,on which the substrate is placed, is coated with an amorphous siliconoxide film, wherein the amorphous silicon oxide film coating thesubstrate-placing face of the supporting portion is formed by theheat-treating.